The invention relates to a process for processing a sliver which is produced in a first machine and is deposited in containers and which is processed from the containers by a second machine which is connected with the first machine by means of a conveying device for the containers. The invention also relates to a machine arrangement for the processing of the sliver.
It is known (German Patent DD-PS No. 107 952) to feed to a fine-spinning machine, particularly an open-end spinning machine, a sliver in large spinning cans, the contents of which are transferred to small spinning cans by means of a transfer arrangement. The small spinning cans move past the spinning units and past a transfer station in a circulating conveying device and are, as required, applied to the spinning units. In this case, it is known to "solder together", i.e., to connect by rubbing, the end portion of the sliver running out of one of the small spinning cans with the starting portion of the next spinning can.
It is also known (SU-PS 213 644) to introduce a sliver automatically into an aerodynamic open-end spinning machine after an exchange of cans. At the fed cans, a free end portion of the sliver hangs down which is held in a clamped manner at a predetermined point. Before the introduction, the can is aligned with respect to the spinning machine by means of a magnet arranged under the can bottom.
It is also known (German Unexamined Published patent application DE-OS No. 34 40 598) to carry out the exchange of cans by means of a movable cart which is equipped with grippers for the cans. In this construction, the end portion of the sliver is fixed at the can by means of a clamp which is positioned opposite a spinning unit to which the can is applied.
It is also known (German Unexamined Published patent application DE-OS No. 35 01 875, corresponding to U.S. Pat. No. 4,653,263 dated Mar. 31, 1987) to carry out the piecing of a new sliver in the case of an open-end spinning arrangement in such a manner that the yarn count is not changed. Also in this construction, the end portion of the sliver filled into a can is held, in a clamped manner, at the can. This end portion is scanned, after which the can is positioned relative to the spinning unit.
It is also known (German Patent DE-PS No. 25 36 435) to carry out the exchange of cans by means of a movable cart which is equipped with a depositing plate for full cans and a depositing plate for empty cans. The cart has a circulating belt which is equipped with clamps at which the individual end portions of the sliver are held. The mentioned belt brings the clamps with the end portions of the sliver into a specified position in the area of the spinning unit at which the exchange of cans is to be carried out. There, the sliver is taken over by another clamp and is introduced into the spinning unit.
It is also known (European Patent EP-PS No. 69 087) to sense and grip an end portion of a sliver hanging out of a can. For this purpose, sensors are provided which have photoelectric cells, to which clamping jaws are assigned. The cans or the sensors are rotated until the end portion of the sliver is located in the area of the clamping jaws.
It is known (European Patent EP-OS No. 220 945) to search for the end portion of the sliver hanging downward at a can after leaving a first drafting unit in the area of the drafting unit which follows and to grip this end portion of the sliver by means of a gripper. The gripper will then introduce the end portion of the sliver into the second drafting unit.
It is also known (German Unexamined Published patent application DE-OS No. 27 54 914) to provide cans which contain sliver with an electrically or electronically detectable coding, for example, in the form of colored strips which are read by a decoding apparatus of the spinning machine, whereby it is prevented that a wrong sliver is presented at this spinning machine.
An object of the invention is to provide a process of the initially mentioned type by means of which the automatic processing can be carried out more securely.
This object is achieved according to the invention in that, at the first machine, the end portion of the sliver deposited in each container is gripped automatically and is fed to a preset point of the container and is fixed there.
The sliver end portion of the sliver quantity deposited in the container, which represents the starting portion of the sliver in the next machine, is therefore no longer left to itself at any time, so that work can take place with a high degree of security. In contrast, it is provided in all prior art that the sliver either is not brought into a specific position of the sliver container before it reaches the machine processing the sliver further or, at the earliest, during the conveying. This means that, on the one hand, in the case of the processing machine, increased expenditures are required for the searching for the end portion of the sliver, while, on the other hand, there is the danger that, during the transfer to the conveying device and during the conveying, the end portion of the sliver will be lost. During a fully automated operation, such arrangement will as a rule result in considerable difficulties.
In a development of certain preferred embodiments of the invention, a machine arrangement is provided for the processing of sliver, in which automatically operating devices are assigned to the first machine for the gripping of the end portion of the sliver deposited in each container and for the fixing of this end portion at a preset point of the respective container. Also in this development, the end portion of the sliver is taken up immediately and, during the whole time, is held securely until the further processing in the machine which follows.
In a further development of certain preferred embodiments of the invention, devices are provided for separating the end portion of the sliver filled into a container from the sliver running out of the first machine. In an advantageous further development, the devices for the separating are constructed as one or several elements which spread apart the sliver. As a result, the end portion of the sliver is thinned out a little. At the same time, the starting portion, which runs into a can, is also thinned out. When these two parts are connected with one another during an exchange of cans at the machine processing the sliver, for example, by means of rubbing, a connecting point is created which approximately contains a fiber amount which corresponds to the amount of fibers of the other areas of the sliver. As a result, an exchange of cans may take place without stopping the respective spinning unit and without the occurrence of an unacceptable yarn defect.
In a further development of certain preferred embodiments of the invention, it is provided that each container is equipped with devices for holding fast the end portion of the sliver filled into the container. In a further development, it is provided in this case, that the devices for holding fast the end portion of the sliver filled into a container are mounted detachably at the container. As a result, it becomes possible to continue to use the containers used up to now and to retool them with these devices.
According to further developments of certain preferred embodiments of the invention, it is advantageous to assign to the devices for holding fast the end portion of the sliver placed in a container an additional function, so that they have an additional value. In an expedient development, it is provided that the devices for holding fast the end portions of the sliver filled into a container are equipped with an element which is assigned to a positioning device. This may, for example, be a counterpart which matches a gripper of the positioning device.
In another development of certain preferred embodiments of the invention, it is provided that the devices for holding fast the end portion of the sliver deposited in a container are provided with elements which can code information concerning the sliver.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein: